<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <script src="http://g.tbcdn.cn/mtb/lib-flexible/0.3.4/??flexible_css.js,flexible.js"></script>

    <title>Title</title>
</head>
<body>
   <div style="width:10rem;height:10rem;background:red;"></div>
</body>
</html>